1. Field of the Invention
The present invention relates to an apparatus to control an internal combustion engine, a method for controlling an internal combustion engine, and a non-transitory computer-readable recording medium having program code stored thereon which, when executed by a computer, causes the computer to perform an internal combustion engine controlling method for performing a plurality of application programs.
2. Description of the Related Art
A cylinder deactivation operation to deactivate part of multiple cylinders in an internal combustion engine having the cylinder deactivation mechanism has a problem in that the spark plugs of deactivated cylinders are fouled (fouling caused by adhesion of carbon mainly occurs) to be likely to cause accidental fire. Japanese Examined Patent Application Publication No. 1-19056 discloses a control apparatus in which a spark plug fouling detecting unit is provided in order to resolve the above problem and the cylinder deactivation operation is prohibited if a parameter indicating the fouling state of a spark plug detected by the spark plug fouling detecting unit reaches a threshold limit value of firing.
Since it is necessary to provide the spark plug fouling detecting unit in the control apparatus disclosed in Japanese Examined Patent Application Publication No. 1-19056, complicated structure and an increase in cost are caused. Methods of prohibiting the cylinder deactivation operation, for example, if the duration time of the cylinder deactivation operation exceeds a certain determination time can be supposed. However, it is not possible to achieve sufficient antifouling effect by such a method if the cylinder deactivation operation having shorter duration time is frequently performed.